I worked out what the problem was - following Nat's suggestion (in a very long and detailed response: thanks again!) I stripped the logic board and cleaned out all the ram sockets and the rom socket. I think the latter was the problem, there was a bit of lint caught in between two of the teeth. According to a post on the 68k mac liberation army's site this is a frequent cause of problems with these machines.
This has also fixed the lengthy delay between startup chime and happy mac, which according to repair mac (http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html) is an early symptom of simasimac, the horizontal lines of death.
Thanks to everyone for their help.
Cheers, Charlie
-- Compact Macs is sponsored by <http://lowendmac.com/>.
Support Low End Mac <http://lowendmac.com/lists/support.html>
Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/>
---------------------------------------------------------------
The Think Different Store
http://www.ThinkDifferentStore.com ---------------------------------------------------------------
